Motor



W. ERNST Dec. 8, 1942.

MOTOR Original Filed May 5,1939

P BL,

.Trwe/u WALTER ERNST,

' jects wherein 'a single pressure pressure fluid to both the booster ram area and the main ram Patented 8,: 1942 Walter Ernst,

The Hydraulic mington, Del.,

Mount Gilead, Ohio, assignor to Development Corp a corporation of Delaware lnc., Wilbriginal application May 5, 1939, Serial No.

Divided and this application October 5, 1939, Serial- No. zoaosa 2 Claims. (Cl. 121-38) This invention relates to hydraulic machinery,

and in particular, to hydraulic press systems.

One object of this invention is to provide a hydraulic press system having a hollow main ram with a booster area in a booster chamber, and an adjustable booster ram therein, arranged initially to supply pressure fluid to the booster area and subsequently to automatically supply pressure fluid to the main ram area after the main ram has traveled a predetermined variable. distance, dependent upon the adjustment booster ram.

Another object is toprovide a hydraulic press system having a main ram with a main ram area of the and a booster area within the main ram, and a fluid passageway interconnecting the main ram area with the booster area, the pressure fluid being conveyed to the booster area by means of a fixed booster plunger having a bore therethrough, the head of the fixed plunger being adapted to uncover one end of the passageway after the main ram has moved a predetermined distance so that the pressure fluid flows into the booster ram the main ram chamber 50 as to apply the full force ofthe pressure the main ram.

Another object is to provide a hydraulic press system of the type set forth in the preceding obfluid connection sumces for the supplying of area. i Another object is to provide a hydraulic press system having a ram within a cylinder, together with a by-pass passageway interconnecting the cylinder bore portions on opposite sides of the piston head of the ram, this passageway having a plurality of spaced ports so as to cause by-passing of the fluid and halting of the plunger at one of a plurality of predetermined positions.

This application is a division of my application, Serial No. 272,011, filed May 5, 1939.

In the drawing: Figure 1 is a grammatic view, partly in sec tion, showing the hydraulic press system of this invention in a preferred embodiment.

Figure 2 Ban enlarged view of a portion of Figure 1, showing the multiple by-pass ports and check valves associated with them. 4

In general, the hydraulic. press system of this invention consists of a main cylinder having a main ram area and main chamber connected to a combination check and unloading valve, which,

a in turn, communicate with a fluid reservoir, such chamber and then through the passageway to fluid to the-entire area of v pressure cordingly to vary as an oil tank. The main provided with a central chamber into which a ton is hollow and valve chamber is a the invention as applied to a of pumps I I distribution of the pressure art, such variable ram is hollow, being stationary piston projects. This'stationary pistrol valves. The main ram is'provided with one or more internal passageways opening into the chamber within the main ram which are arranged to be uncovered as the main ram travels relatively to the head of the stationary hollow piston. In this is first conveyed through the hollow piston to the central or booster chamber of the main ram and after the latter has traveled a predetermined distance this fluid also reaches through the passageways.

The combination check and connected to the main ram chamber consists of a single casing having two chambers, namely a check valve chamber and an unloading valve chamber. A ball member is fro within the check valve chamber, whereas a spring rurged plunger reciprocates in the unloading 'valve chamber, Above the unloading separate plunger lifting pressure fluid may be admitted plunger to lift, the check chamber to which to cause the unloading valve valve chambe I chamber to a discharge conduit. conduit may lead to the fluid reservoir such as an oil tank.

Referring to the drawing shows diagrammatically the in detail, Figure 1 hydraulic system of plastic injection molding press. The press, generally designated 10, is supplied with pressure fluid from a pair I and I2 driven II and I2 is regulated by a pair of four way valves H and I5, these valves being arranged to be shifted either by the operator or by automatic .means. The details of the construction of these pumps and valves form no part of the present invention. 'Also associated with the circuit is a combination check and unloading valve IS. A pair of safety valves i1 and I8 serve to release fluid in the event of the failure of other safety devices. The pumps II and i2 are preferably of the variable-delivery type having a flow, control member which is movable to vary the amount of reciprocation of the the'rate of discharge of the pumps. As is well-known to those skilled in the delivery pumps are usually at its outer end is connected to a source of pressure fluid through suitable conthrough ports,

manner pressure fluidthe main ram area unloading valve free to move to and- This discharge by a motor IS. The fluid from the pumps pistons and -ac--v .nected to the pump H.

supplied with mechanism for automatically shifting these flow control members to neutral positions when the pressure conduit 36 leading to the oil tank 31, and likewise with' a pressure fluid inlet conduit 38 con- I The pump II is provided with a suction conduit 39 opening into the oil tank 31. The safety valve I1 is connected by the conduit 40 provided with a pair of additional ports 42 and 43 interconnected 'by the conduit 44 containing the ball check valve 45. This arrangement serves to halt the retraction of the piston 23 when it or die mounted upon the The die head 46 is relatively stationary but is capableof a limited amount of motion for cushioning. purposes. For this reason the die head 46 is mounted upon a plurality of cushioning pistons 49 (one only being shown), these reciprocating in die cushioning cylinder 50. The piston 49 is connected to the die head means of a piston rod and a tail rod tends in the opposite 52 exdirection from the piston 49. The piston rod 5| and tail rod 52 are provided with longitudinal passageways 53 and 54 leading respectively to conduits 55 and 56. These conduits are connected as described below.

The die clamping unit l9 consists of a cylinder 5'! within which the main ram 58 reciprocates.

age around the piston rod 6| is prevented by a gland 62 and spaced packings 63 and 66 separated by a chamber 65. port 66 is connected to the drainage conduit 61 leading downward to the tank 31.

The piston rod BI is provided with an internal the end 69 of which forms the so-called the bore 68 are ports 70 having passageways H to the main ram area 12 on the end of the piston head 60, the opposite end 73 of which forms the retraction area. On the opposite side of the main ram piston head 60, when the latter is in its retracted position, are spaced ports 14 and I5 interconnected by a bypath passageway 16.

of pressure fluid. Also connected to the valve i5 is an exhaust conduit 19 discharging into the oil tank 31. A port conduit leads from of way of the connection cap 82. The port 8| leads into a passageway or chamber 83 surrounding the piston rod 84. The chamber 83 is closed by an end plate 85. The piston rod 84 carries a piston head 86 fitting smoothly into the bore 68 within the main ram 58. Piston rod 84 and piston head 86 are traversed by an L shaped latter the exhaust the oil tank 31.

and 93 lead into The pump I2 is provided with which discharges into the tank 31.

The combination check and unloading valve l3 consists of a casing having a chamber for receiving a ball check valve member 99 which is engageable with an annular seat in the form of a sleeve coaxial with the said chamber.

From the latter the left of the main ram area line 38 to the conduit ber, housing the ball check valve member 33, and the exhaust conduit 83. 7

Operation In the operation of the hydraulic press system of this invention the operator starts the motor I3, therebyplacing in operation the pumps II and I2. Assuming the parts of the press III to be in the retracted positions shown in Figure l, the operator now operatesthe clamping control valve I and the injection control valve I4 to operate the press III in its various movements.

To clamp the dies, the operator shifts the valve member I20 of the clamping control valve upwardly, thereby placing the pressure conduit 82 in communication with the conduit 83. Pressure fluid then flows from the pump I2 through the conduits 82 and 80 to the port 8I, thence into the chamber 83 and through the piston rod passageway 81 into the end of the ram chamber 58 adjacent the booster area 69 thereof. As the latter area is of relatively small diameter, the main ram 58 and platen 59 move forward at a relatively rapid rate. Meanwhile, the fluid in front of the ram head 68 is discharged through the port", the conduit I8, the valve l5 and the exhaust conduit I9 into the oil tank 3'9.

When the main ram 58 has traveled forward to a point where the ports III are uncovered in passing the stationary piston head 86 the pressure fluid within the through the ports 10 and passageways It into the rearward end of the main cylinder 51 to the I2. The full pressing force is now exerted upon the platen 59 and the die or mold halves are held firmly together with a very great force. I I

While this is occurring pressure fluid also flows through the conduit inder 50 and thereby yleldingly supports the die head 46 and the die or mold half carried thereby. The fluid on the opposite side of the'piston head 49 escapes through the conduit 56 to the conduit 18 and thence to the exhaust conduit l3 and the tank 31 by way of the clamping control valve 85. When the desired clamping pressure has been reached, the flow control member of the pump it automatically shifts to its neutral position. Meanwhile, as the main ram 58 has advanced, fluid is drawn into the rearward end of the main cylinder bl through the pipe ti and past the ball check valve member 99, which is raised by the suction thus created. In this manner,

fluid passes upwardly from the oil tank 31! through the pipes 92 and SI to the main cylinder 51.

the main cylinder 51, however, this pressure immediately closes the ball check valve member 99 2 upon its seat, aided by gravity.

To perform an injection stroke after having placed injection molding material in the hopper 28 and suitably heated the injection cylinder 25, the operator shifts the valve member I2I of the injection control valve I4 upwardly, thereby admitting pressure fluid from the pump discharge hand end of the injection operating cylinder 22. This pressure acts against the piston head 23 and pushes it and the piston rod 24, together with the injection moldingmaterial throughthe bore 28 and out the nozzle, 21 into the channel or passageway 48 from whence it passes into the mold cavity between the mold halves.

To retract the injector, the operator moves the 55 into the cushioning cyl When pressure enters the rearward end of 30' booster chamber 53 escapes the clamping plunger 34 and thence into the right valve member I2I downward aided by the coil spring I23 so that the injector piston 23 is reversed, pressure fluid entering through the conduit 35 and the displaced fluid returning to the tank through the conduit 34 and the exhaust conduit 33. When the piston head 23 passes the port 43 in the cylinder 22, fluid then flows through the conduit the check valve 45 into the right hand end of the cylinder 22, then through the conduits 34 and 36 into the tank 31, thenceforth by-passing the discharge of the pump II andhalting the retrac tion of the piston head 23.

To unclamp the dies or mold halves, the operator moves the valve member I20 of the clamping control valve I5 downwardly aided by the coil spring' I22. Pressure fluid is now supplied by the pump I2 through the line 18 and port 11 to the retraction side 13 of the main ram head 58 repressure fluid flows from the conduit18 through the conduit H3 to the plunger lifting chamber of the unloading valve plunger, lifting the'latter and opening the check valve chamber into communication with the exhaust conduit 93." The fluid displaced from the left-hand end of the main cylinder 51 then is permitted to pass through the conduit 9I, into the check valve chamber, thence into the exhaust conduit 93. When the piston head 60 arrives at the position shown in Figure 1, it uncovers the port I5, whereupon the fluid is bypassed around the piston head 50, halting the further travel thereof. At the same time, 49 moves backward and ends its cushioning action. The foregoing cycle of operation can then be repeated in the same manner.

The piston-rod 84 is means, piston rod 84 may be rotated so as to advance or retract the head 86 longitudinally. This arrangement, by reason of the threaded mounting of the threaded portion 88 in the threaded bore 89 and the annular chamber 33, enables the point at which the head 88 uncovers the ports I0 to be varied as the main ram 58 advances.

provided with suitable rately to diflerent thicknesses of dies mounted upon the die carriers 46 and 59.

The construction shown in Figure 2,-and on a smaller scale in Figure l, is for the purpose of causing the halting of the piston head 39 at different points on its retraction stroke. A press of this type frequently employs dies of different thicknesses, depending upon the kind of workpiece to be molded. It is necessary, in designing such a press, to provide for a sumcient retraction of the main ram 58 to enable the use of the thickest dies likely to be encountered in ordinary practice. When thin dies are used, such as for the making of thin work-pieces, valuable time is lost in retracting the main or clamping plunger 58 to a greater distance than is necessary for opening the dies and ejecting the work-piece. The arrangement shown in Figures 1 and 2 enables the apparatus'to be adjusted so that for thin dies the main ram or clamping ram 58 will be retracted a shorter distance than with thick the flow of pressure fluid to I 44 and past- 58 from its Figure 2 posi- 1 such as the squared end I30, whereby the 7 By this arrangement the apparatus can be adjusted accument shown in Figure 5 containing bail check valves I45 and I46. Opposite the valve seats I43 and I44 are threaded ports I47 and 548, into which screws I49 and I50 are threaded. By rotating these screws to bring their inner ends into engagement with the balls I45 and I56, the ports MI and I42 may be positively closed so that the ram head 60 will not halt until it uncoversthe port 15. If, however, it is'desired to halt the ram head at an intermediate port, the screw I49 is rotated in a reverse direction so as to permit the ball I45 to move. Accordingly, when the ram head 60 uncovers the port IiI on its retraction stroke, the ball I45 will be forced away from its seat I43, thereby permitting fluid to flow through the port MI and the by-pass passageway I6, through the port I4, into the opposite end of the cylinder 57, halting the retraction of the main or clamping ram 58.

If extremely thin dies are to be used, the screw I56 is also rotated to free the ball check valve M6. Accordingly, when the port I42 'is uncovered by the ram head 60, during the retraction stroke, pressure fluid will flow through the port I42 into the by-pass passageway I6, after raising the ball check valve I46 away from its seat I44. Thus, the ram head 60 will halt after a shorter retraction stroke than if the port I4I or- I the port I5 were employed.

The screws I49 and I50 may either be solid or may be provided with sockets I5I, with springs I52 engaging the ball check valves I45 and I46. Caps I53 are provided for covering the ends of the screws I49 and I50 so as to discourage tampering with the adjustment thereon Lock-' nuts I54 may also be optionally provided to lock the screws I49 and I50 in their adjusted positions. The operation of the by-pass arrangehas been described in connection with its construction, and requires no further description.

It will be understood that I desire to comprehend within my invention-such modifications as come within the scope of the claims.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

.1. In a hydraulic press, a cylinder having reciprocably mounted therein a piston with an aidvancing and a retraction side, a by-pass conduit provided with three laterally spaced ports, of which two adjacent ports continuously communicate with said cylinder, a check valve associated with the third port and controlling hydraulic communication between said cylinder ously connected with said cylinder but normally not connected with said by-pass conduit, said said cylinder, while one of the first two mentioned ports is located adjacent the opposite end of said cylinder, and means for selectively connecting said by-pass conduit with an exhaust and said fourth port with a pressure fluid source, or said fourth port with an exhaust and said bypass conduit with a pressure fluid source.

2. In a hydraulic press, a cylinder having reciprocably mounted therein a piston with an advancing and a I one end of said by-pass passageway being continuouslyin hydraulic communication with said cylinder, wherefor alternately connecting said by-pass passage- 

